Change cell reference depending on date

Hi Guys,

The spreadsheet attached is a timesheet I use.

The last column on the sheet (IV) keeps a running total of time spent on each project.

I need a way that i can find out how much time was spent on projects in specific timeframes (eg 01/01/09 - 07/01/01, or 01/01/09 - 31/01/09)

my initial thought is perhaps i can have a "from" cell and a "to" cell to input the dates i require and it will total the relevant cells in the rows below.

PLEASE NOTE! This workbook uses VBA to auto hide any column which are dates previous to today's date so you may need to unhide them to view times logged.

Any help would be greatly appreciated